CD4+CD25+ Regulatory T Cells in Patients with Advanced Gastrointestinal Cancer Treated with Chemotherapy

Background: The prevalence of CD4(+)CD25(+) regulatory T cells (Tregs) and other T-cell subsets in gastrointestinal cancer patients treated with chemotherapy was investigated. Patients and Methods: The frequencies of Tregs and other T-cell subsets in the peripheral blood of 25 healthy donors and 104 patients with gastrointestinal cancer were measured by flow cytometry. Their plasma cytokine levels were determined by enzyme-linked immunosorbent assay (ELISA). The percentages of the T-cell subsets and their correlation with the outcomes of the gastrointestinal cancer patients after chemotherapy were evaluated. Results: Not only was the prevalence of Tregs in the peripheral blood of gastrointestinal cancer patients significantly higher than that in healthy donors, but it also increased in parallel with tumor progression. Among patients with advanced disease, 3 weeks after chemotherapy, those with higher percentages of Tregs had a poorer prognosis. Interleukin (IL)-2 production showed a reverse trend to Tregs, whereas IL-10 and tumor necrosis factor (TNF)-alpha did not change significantly. Conclusions: The relative increase in CD4(+)CD25(+) Tregs may be related to immunosuppression and tumor progression in patients with gastrointestinal cancer. Chemotherapy in patients with advanced disease showed that immunosuppression is enhanced early (about 1-2 weeks) after chemotherapy, and increased Tregs 3 weeks after chemotherapy correlated with a poor prognosis.